Jh. Miwa et al., Improved acidolytic deprotection conditions for the Fmoc-based solid-phasesynthesis of thioxo peptides, TETRAHEDR L, 42(41), 2001, pp. 7189-7191
The acid-mediated cleavage of a synthetic thioxo peptide was monitored usin
g deprotection cocktails with varying concentrations of TFA. Thioxo peptide
s are acid labile, undergoing cleavage at the amide linkage immediately fol
lowing the thioamide linkage in the sequence, This acid lability makes Fmoc
-based synthesis the method of choice for thioxo peptide preparation. The e
xtent of cleavage increases with increased TFA concentration and longer rea
ction time. Data presented herein indicate that deprotection protocols invo
lving low TFA concentration (ca. 80%) and short reaction times (ca. 2 h) mi
nimize the losses due to acidolytic cleavage. (C) 2001 Elsevier Science Ltd
. All rights reserved.